1. Field of the Invention
The present invention relates broadly to retainer assemblies for securing objects, particularly elongated objects and more particularly to a plastic avionic wire clamp assembly for providing a removable lightweight securement of aircraft electrical wires, cables and the like.
2. Description of the Prior Art
As can be readily appreciated by anyone familiar with the construction of commercial and military aircraft, the advent of highly sophisticated electronic equipment has greatly increased the wiring requirements of aircraft.
Aircraft wiring is presently supported by stainless steel aluminum loop type clamps that are provided with an elastomeric cushion. The main purposes of the elastomeric cushion are to prevent the wires from contacting the metal clamp band, to provide a high frictional surface between the wires and the band and to prevent wire bundle axial movement. Experience has proven that the elastomeric cushions are subject to damage from mechanical abuse near access areas, from hydrocarbon fluid attack, and from weather cracking such as a result of ozone oxidation. Frequently, the wires will contact the metal band which will result in failure of the wire installation. An exposed clamp band subject to vibration can cut through the installation of the wire during a flight causing damage with no chance of inspection. The result can range from a nuisance loss of a minor electrical circuit to a more serious loss of an important navigational system circuit or a control circuit on a fly by wire system. Fires can even be occasioned by short circuits which have damaged aircraft.
An additional drawback of the conventional avionic clamp assemblies is that they require installation in the airplane and cannot be preassembled outside of the plane. Usually, the individual wire clamps are mounted on a tree and if repair is required on a lower cable then the entire tree must be disassembled. Generally, these clamp assemblies are mounted on 18 inch spaces and their combined weight can be of relative significance with regards to the ultimate pay load of the plane. Additional problems associated with the conventional avionic wire clamps are that they can be subjectively tightened by a repairman to a distructive mode force and they are further capable of loosening under normal in-flight vibration.
Various forms of plastic cable ties are known in the patent literature such as U.S. Pat. No. 2,936,980, U.S. Pat. No. 2,955,328, U.S. Pat. No. 3,537,146, U.S. Pat. No. 3,570,497, U.S. Pat. No. 3,660,869, and U.S. Pat. No. 3,900,922. These patents are representative of a relatively crowded state of art. These references, however, do not offer a solution to the specific problems that are encountered in the hostile environment of aircraft nor to the ever present problem of the subjective capability of the operator to exert an excessive amount of force on the retained objects. Accordingly, the prior art is still seeking a solution to these general problems and more specifically a solution to the problems specifically encountered in the aircraft industry.